Mpl ligand promotes survival of hematopoietic progenitor cells.

Mice were given 80 mg/kg carboplatin intravenously, and 7.5 Gy Cs-137 TBI, then either PEG-rmMGDF or carrier (1-2 mice per group). Bone marrow cells were collected 1 (middle panel) or 2 (bottom panel) days later and plated in methylcellulose-containing medium with IL-3 (2 dishes per bone marrow sample). Colonies were scored on day 13, and colony sizes were classified as large (> 500 cells/colony), medium (200-400 cells/colony), or small (15-150 cells/colony). Untreated (top panel) colonies formed from bone marrow collected from mice that received no carboplatin/TBI. Bars represent means ± SEM.